RG58 Compared to LMR-200 & LMR-100 Coax: Shielding & Signal Loss

RG58 Coaxial Cable Specifications

RG58, LMR-100 and LMR-200 all have the following characteristics in common:

• 50 Ohm impedance
• A weather-resilient polyethylene (PE) dielectric
• PVC outer jacket

Structural comparison of RG58 and LMR-100 (aside from what is mentioned above):

• LMR-100 is a 50 Ohm coaxial cable which shares structural and material similarities with RG58, but has an overall lower diameter of 2.79mm (0.110 inches).
• RG58 and LMR-100 have the following key differences:
  
  • LMR-100 carries a solid bare copper-covered steel (BCCS) central conductor of 0.46mm.
  • LMR-100 is a double shielded coaxial cable. The inner shield is made from aluminum tape and the outer shield of braided, tinned copper.

Structural comparison of RG58 and LMR-200 (aside from what is mentioned in the first paragraph above):

• LMR-200 is a larger diameter (6.1mm 0.24inches) low loss coaxial cable that has double shielding (meaning less loss of signal along the length of the cable), with braided tinned copper and aluminum tape layers coating the dielectric and inner conductor.
• LMR-200 possesses a larger conductor of 1.42mm diameter made from bare copper (BC) 

About RG58

Electrical characteristics of RG58: The typical impedance is within a 2 Ohm range of 50 Ohm. It operates at frequencies up to 5GHz. The conductor resistance is 38.4 Ohm. The dielectric resistance is 500 Ohm.

Structure and material composition of RG58 cable

Like all other coaxial cable, RG58 comprises an inner conducting wire, surrounded by and insulating layer and outer conducting shielding. RG58 coax cable is typically manufactured to the U.S. specifications MIL-C-17F and MIL-C-17G 9.

• The conductor has a diameter of 0.91mm (0.036 inches) and is made from stranded (7 or 19 strand), tinned copper wire, which has added resistance to oxidation and is readily soldered. Solid conductor variants are also available.
• The dielectric diameter is 2.95mm (0.116 inches) and is made from solid polyethylene (PE). Polythene is heat stable up to a maximum operating temperature of 80 degrees Celsius (176 degrees Fahrenheit), provides flexibility, fire resistance, resilience against abrasions and  weatherproofing.
• RG58 is shielded with flexible and heat stable tinned copper wire braid with coverage of between 70% and 95% depending on manufacturer.
• The outer jacket of RG58 cable is made from UV-resistant PVC, which is heat-stable but has limited resistance to acids, alkalis and inorganic solvents.
• The overall diameter of this cable is 5mm (0.2 inches).

RG58 is a coaxial cable type for antenna cables, made to strict U.S government specifications. The ‘RG’ pre-fix stands for ‘Radio Frequency Government’ and the number refers to the gauge of the cable.

RG58 applications

This coax cable performs well for a variety of radio frequency communication applications in a low-power setting. Key applications include:

• Testing and measurement
• Ham and emergency services radio
• Marine VHF
• WLAN antennas

RG standard of Coaxial Cable

RG is a robust coaxial technology standard - one of the original standards for coaxial cable technology, created for the US military in the 1960's. RG is not a certain manufacturer's standard: All coax manufacturers can use RG and a standard, by using the letters RG (stands for "Radio Guide") followed by a number which corresponds to a certain standard with a particular set of specifications. Sometimes, the letter "/U" follows the number, for the "Universal" standard (i.e., the cable construction is intended for universal applications).

There is no standardization to ensure every aspect of the cable is constant among manufacturers, so it helps to know the specifications of the cable you need.

RG technology is used in military and commercial applications in a wide range of environments.

Generally, 75 Ohm cables are used in audio/video applications, and 50 Ohm cables are used in data applications. The 50 Ohm RG cables generally lose too much signal through  attenuation, to be appropriate for wireless applications, unless the cable is short. For longer lengths of antenna cables, low-loss coax is the only viable solution.